Variable interval stepping switch



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dfi/W55 5. 60556719 LTI E f IA vvl 2.. mt/l. ,1, in @Si m5 vvjlllfMNUIWHIIHMIINIJ )man Aug. 3, 1965 J. s. ROBERTS VARIABLE INTERVALSTEPPING SWITCH 9 Sheets-Sheet 9 Filed June 50. 1961 INVENTOR. (J4/W555. 5055675 BY f'Z/VEYS United States Patent O 3,198,967 VARlABiJEllN'iCERl/AL STEPPNG SWITCH .lames S. Roberts, Broold'ield, Wis.,assigner to Milwaukee Chr-.piet 3s Company, inc., Milwaukee, Wis. Filed.lune 3i), 1961, Ser. No. 121,241 12 Ciaims. (El. 367-1414) Divisionalapplication, Serial No. 244,643, filed December 14, 1962, to a DriveMechanism for a Stepping Switch; divisional application, Serial No.244,644, tiled December 14, 1962, to a Stepping Switch and divisionalapplication, Serial No. 244,773, tiled December 14, 1962, to a MountingStructure for a Timer of this invention are now co-pending.

This invention relates to a means for controlling a sequence ofoperations and more particularly relates to that class of electricalswitching means known as a stepping switch. The invention has specialreference to a stepping switch with mechanical and electrical means forstepwise operation to control a sequence of events.

Stepping switches as heretofore commonly known in the art have includeda memory device on which is structurally coded a predetermined program.The coded structure ordinarily represents and actuates a desiredsequence of switching operations. Each switching operation in turncontrols one or more events such as operating a machine, admittingliquid into a tank, closing a valve or the like. The coded structure ofthe memory device accomplishes this by manipulating switches which thestructure engages or disengages in the course of operation.

As a general rule the memory device of such stepping switches is anintermittently rotated member. The intermittent rotation moves themember a fraction of a circle each time, dwells at the new position forsome predetermined period of time, then moves to another position inlike fashion and dwells again. This moving and dwelling during rotationis termed stepping Ordinarily, the fraction of a circle moved and thelength of time that the prior art stepping switches dwell are the sameas between any two successive cycles of intermittent rotations. Thisrestricts the time limits of the thing controlled to multiples of thesingle dwell period since the switches manipulated by the memory deviceare maintained in (or out of) position during the dwell period, orduring successively occurring dwell periods if the memory structure sodictates. Where the control program of the thing controlled requireswidely varying control (or dwell) periods, it may be diilicult if notimpossible to program adequately on the memory device. Physical spacingis one reason for this. Further, some controlled systems requireinterruption of the time sequencing when certain events transpire, e.q.a temperature rises too high, a fluid flow drops too low, or a chemicalconcentration exceeds its allowable tolerance, or a machine fails toperform properly: prior art stepping switches have often required verycumbersome construction to accommodate such interruptions and thencontinue with the stepping, and some could not do so at all.

United States Patent No. 2,784,786 issued to F. A. Pearson on March 5,1957, for a Stepping Switch Apparatus7 is exemplary of the prior art.

The present invention, although it transcends the same, embodies certainfeatures set forth in the copending United States application tiledOctober 9, 1959, by myself and Elmer S. Welch, Serial No. 845,480 for aProgram Controller, now U.S. Patent No. 3,101,435 granted August 20,1963.

A primary object of the invention is the provision of a stepping switchhaving different dwell time intervals arranged in a predeterminedpattern or sequence.

Another object of the invention is a stepping switch arranged to dwellfor a selected one of a plurality of Patented Aug. 3, 1955 ice discretetime intervals in a predetermined selection sequence.

Still another object of the invention is a stepping switch arranged todwell in a predetermined sequence for time intervals, other thandiscrete time intervals, of respectively diiferent predeterminedlengths.

A further object of the invention is a stepping switch constructionallowing a response to an interruption by some event other than time butwhich resumes stepping in a predetermined fashion after suchinterruption.

Still another object of the invention is the provision of a steppingswitch system having one or more stepping switches each of which iscompatible enough with the others to be connected in master-slaverelation whereby one or more of the foregoing respective objects areaccomplished.

An object of the invention is a stepping switch construction allowingchanging of the memory device whereby an entirely new program isachieved by substituting a new memory for an old one.

The invention has as an object a stepping switch hav ing any single oneor any combination of the foregoing objects.

The presently disclosed embodiment of the invention is adaptable eitherto controlling operations continuously or to manual initiation when adesired sequence of operation is to be carried out. A stepping switchconstructed in accordance with the invention is particularly well suitedfor controlling the processing of dairy products, for example, tocontrol operations for pasteurizing or for controlling so called cleanin place operations. The latter, for example, involves cleaning thevarious pipes, valves, treating vessels, and the like by a sequence ofverifying if the same are free of materials being processed, rinsing thedairy system with cold water, rinsing with hot water, contacting andcleaning with an alkali solution, contacting and treating with an acidsolution, and then rinsing the whole thoroughly to remove all cleaningchemicals. The cleaning operation is ordinarily manually started by theoperator but the different steps are carried out automatically untilcleaning is completed. To facilitate proper starting procedures, and toadvise when the process has been completed, various signalling means mayalso be provided. Signal lights, buzzers, or the like are exemplary ofsuch signalling means. irrespective of the specific use to which thepresent stepping switch may be put, the essential objects, features andadvantages of the invention are at all times preserved.

Briefly, the invention in one form thereof includes a hollow perforatedcylinder or drum fitted with removable pins. The drum and pinsconstitute the memory device. The program is coded by the placement ofthe pins. The pins are arranged in rows extending both axially andperipherally of the drum. Each peripheral row of pins is aligned with asuitable switch. Each axial (lengthwise) pin row represents a timeinterval in the program. Certain perpiheral rows of pins represent theprogram or channel selectors if there is more than one program stored onthe drum. A second peripheral group of pins represents a means toconnect the motor driving the drum with an appropriate time intervalsignal source (eg. a clock timer) whereby the drum is caused to dwell,thereby to move in a stepping manner. Dwell is achieved by stopping themotor. Still a third group of pins and their corresponding switches isarranged to control some function or machine element in the processwhich is to be carried out; there can be one or a plurality offunctions, machines, etc. simultaneously controlled.

In the preferred embodiment, the three groups of pins are arrangedaxially on the drum. When one pin in each group is aligned axiaily, acontrol function is achieved. in some instances, as detailed below,absence of an axial pin may initiate or terminate a control function. Asthe drum is stepped around its cycle, respective pins make and breakvarious electrical circuits to carry out the control and steppingfunctions. The length of time for a given control function is in partdetermined by the peripheral length lof a pin row.

While running, a stepping switch according to the invention causes thedrum to rotate through a predetermined angle, then to stop and dwellthere for a predetermined time interval, and then to repeat until acomplete cycle has been run through. When the drum (i.e. motor) stops,the second pin group through electrical means starts a timing means andenables a holding circuit to keep the drum (motor) in position (dweil)during the time interval. During the time interval other electricalmeans have been actuated by the third pin group to bring about thedesired control function. The control function may continue from onetime interval to another, if desired, except where the pins positionedon the drum determine termination of a selected control function such asopening or closing a valve. The control function may be carried out overa period of successive time intervals of either respective discretelengths or the single predetermined length. At the end of the selectedtime interval the drum again steps and either continues or discontinuesthe control function according to the pins set on the drum. Any controlfunction may overlap any other control function (time-or-sequence-wise)to any predetermined extent.

The drum is mounted in unique fashion so that it acts as a housing forthe drum motor and the gear transmission connected betwen the motor anddrum. This arrangement facilitates removal of `one drum and replacementwith another, thereby to change programs. in this fashion, a largenumber of programs can be made up and stored in advance on appropriatedrums. The operator can then place the appropriate drum on the machine',zero it by locating it at its starting position, and then beginoperation.

The invention also contemplates appropriate electrical means forstarting, running, skipping certain operations in accordance withcertain signals, permitting interruption by signals derived from a baseother than time, and resetting or holding the entire apparatus so thatthe cycle may be repeated. One aspect of the electrical means includescertain ones of the switches which are manipulated by the pins.

As pointed out above, there are two species of time base with which weare primarily concerned, one of which is la discrete time interval ofpredetermined length and which is capable of being repeated, and .theother is a time interval of any predetermined length (non-discreteinterval). In a specific embodiment, the discrete time interval meansincludes plural clocks or timers, most advantageously three or more butnot restricted solely thereto, wherein certain of the pins and switchesare employed to select one timer and to disable all the other timers. Inthis fashion, a plurality of discrete time intervals is stored, but onlyone is called into use at a time. In this fashion, the dwell periods arecontrolled and can be any combination of multiples and/ or sums of thetime intervals represented by the respective timing means. Thus, thevarious time intervals can be repeated at will.

With respect to the non-discrete interval circuit, the inventioncomprehends chopping a beam of light in such fashion that aphotoelectri-c cell provides drive pulses to the motor which operatesthe drum. The arrangement is such that the motor steps to its nextposition and then remains still until the disc which chops the lightbeam has moved an appropriate amount. In this fashion, a dwell period ofany predetermined length is provided at any particular time in the cyclewithout being restricted to sums or multiples of discrete timeintervals.

Another feature of the present invention is the provision of certaincircuits associated with the drum motor and the pins which lare sodesigned as to be compatible with either the discrete interval steppingswitch or the non-dis 'ete interval stepping switch as described brieilyabove. This particular feature promotes mass production and facilitatesinterchangeability of parts. Furthermore, it lends stepping switches ofeither character to being connected in master-slave relation one toanother. It is particularly advantageous in the connection of a discreteintei-val timer as a slave to a master non-discrete interval timer.

In connection with the drum or memory drive system, a unique system isprovided whereby the drum is moved to dead center in such fashion thatit is rotated through a predetermined angle each time a stoppin!yoperation takes place. This assures the accuracy of the time intervalsrequired in the control functions. The drum motor and drum are broughtto dead center in such fashion that the dwell period is not upset, atleast within the limits of accuracy of the stepping switch. ln oneparticular embodiment, the drum is arranged with 60 diiierent steps (Le.pins or perforations for receiving the pins) whereby 6 of rotation isprovided for each step.

The respective electrical means also provides for various manualselection switches whereby one particular program can be put inoperation, or whereby the apparatus may be manually operated entirely.

Other objects, advantages and features will become apparent from thefollowing description when read in conjunction with the associateddrawings. Throughout the drawings, the same reference numerals are usedto designate the same parts and the usual convention is employed ofshowing the electrical apparatus in the position assumed when all of theelectricity is cut olf from the circuits. In the drawings:

FIG. l is partial plan view of the memory device, or

rum, showing the relationship of thel drum and associated structure tocertain microswitches engaged during a control program.

FIG. 2 is a partial elevational cross section of a relationship betweenthe drum and switches as seen along section 2 2 of FG. 1.

FiG. 3 is a cross sectional elevation through the drum showing the geartrain along the shaft.

FIG. 3A is a cross sectional end view through 3ra-3a of FIG. 3 showingthe relationship of the dead .centering means of the Geneva drive.

FIG. 4 yis a simplified schematic and partially exploded perspectiveelectro-mechanical view of one embodiment of the invention for operationon a selected one of a plurality of discrete time intervals, presentedfor explanatory purposes.

FIG. 5 is a simplified electric schematic of the embodiment of FIGS. 4,8 and 9, presented primarily for explanatory purposes.

FIGS. 5A, 5B, 5C and 5D are all electric schematics of modifications ofthe system represented by FIG. 5.

FIG. 6 is a simplified schematic and partially exploded perspectiveelectro-mechanical view of one embodiment of the invention forpreferably operating on ori-discrete time intervals.

FIG. 7 is a simplified schematic representation of the electric circuitsof FIGS. 6, 8 and l0, showing the operating portions free of startingmeans and the like presented primariiy for purposes of explanation.

FIG. E represents schematically a function enabling and memory drivingcircuit which is common to both of FIGS. 9 and l0.

FIG. 9 represents schematically a circuit for use with the circuit ofFIG. 8 as a system for a stepping switch that steps by discrete timeintervals, selecting one from a number of such intervals stored in thesystem.

FTG. l0 represents schematically a circuit for use with the circuit ofFlG. 8 as a stepping switch system for stepping in accordance with astored program of time intervals, usually but not necessarily ofnon-discrete lengths.

FIG. l1 is a simplified plan view showing the drum in operating position(solid lines) and in drum-changing position (dotted lines) as permittedby the mounting means.

FIG. 12 is a simplified perspective view of the drum in the operatingposition of FIG. l1.

PIG. 13 is a simplied perspective view of the drum when swung out todrum-changing position.

General A stepping switch constructed in accordance with the inventionincludes a revolvable drum 2 (FIGS. l-4 and ll-l3) mounted adjacent arow of switches H1, H2, Ll, L2, L3 The drum is revolvable through 360 ina series of steps, stopping at the end of each step and dwelling orholding until signalled to step again. The rotation and stopping iscontrolled by electrical means, hereinafter described in more detailwith reference to FIGS. 4 through l0. A plurality of pins such as thehoming pin HP, P1, P2, P3 are located along the length of the drum witheach of the so designated pins being located in rows. Only one homingpin is provided for reasons hereinafter explained. The pins in each row(each row of pins being designated as Pl, P2 correspond to and engagerespective limit switches Ll, L2, L3 The pins actuate and deactuate theswitches to initiate and terminate a series of control functions.Control functions can be carried out simultaneously or individually andin a predetermined sequence.

The pins, which are removable, are only inserted where a controlfunction is desired, thus a predetermined sequence of functions may beset on the drum and thereby bring about the control program responsiveto the stepping rotation of the drum. The time intervals during which acontrol function is carried out are determined by the lengths of timethat the drum dwells at different positions.

One homing pin HP is provided in alignment with the homing switch HI,H2. The homing pin defines the position to which the drum is drivenafter a control program has been completed. When the drum arrives athome, it stays there until another program, or the same program, isbegun all over again.

A plurality of programs may be stored on the drum. Assuming two programsto be stored on the drum, the rows of pins P1 and P2 and theircorresponding limit switches Ll, L2 are arranged to define thosepositions at which the drum dwells. Where there is an absence of pinsPl, P2 there will be no dwelling and the drum will drive to the nextsucceding pin in the row or to the home position. Of course, more thantwo programs may be stored on the drum where space permits.

Where discrete intervals of time are to be employed in stepping thedrum, the rows of pins P3 and P4 along with their corresponding switchesL3 and L4 are employed to select a timing means to provide thepredetermined discrete time interval during which the drum will dwell inthe position to which it has been stepped. As will be hereinafterexplained, it is possible to use two rows of pins P3, P4 to select oneof three timing means. In an alternative embodiment, three pin rows P3,P4 and P5 may be employed to select one of three timers. rfhus, speakinggenerally, two embodiments of discrete interval timers are providedwherein one embodiment requires a pin row for each discrete interval tobe included in the program while the other embodiment uses one less rowof pins than there are discrete interval timers. In the last-mentionedvariety one particular time interval is selected by the absence of anypin P3 and P4 in their respective rows.

Assuming two programs on the drum and that the pins P3 and P4 areemployed for selecting a discrete interval, the rows of pins PS, P6 andtheir corresponding limit switches L5, L6 are employed for selecting acontrol function. The control function is initiated when a pin in theperipheral row engages its correspond- 763 complete cycle.

6 ing limit switch. More than one of the pins P5, P5 may engage itscorresponding limit switch simultaneously. A control function isterminated when no pin is present, in one preferred embodiment.

Thus, in the discrete interval timing means for causing the steppingoperation, at least three pins must be aligned with each other,referring to alignment axially on the drum. The three pins would be theprogram selector pin such as P1, P2; the timer selection pin P3, P4 (orno such pin in one embodiment); and one of the function selecting pinsP5, P6 When such an alignment occurs7 there limit switches are actuatedto both carry out a stepping operation and to select a control function.

Where a variable interval (i.e. non-discrete time interval) is employed,it is still possible to program more than one control cycle on the drumby proper placement of the removable pins. In this case, the programselector pins P1 and P2 again serve their function, and additionalprogram selector pins such as P3, P4 may be used. The other pins on thedrum such as P5', P6 may be used for selecting their particular controlfunction. In this embodiment, two pins, a program pin and a functionpin, are aligned axially on the drum and simultaneously actuate theircorresponding switches, for example, pin Pl and P5 may be aligned.

The memory device 2 and its attendant mechanical and electrical steppingmeans may conveniently be enclosed in any suitable type of cabinet,preferably one that will keep out dirt, dust, moisture, and otherdeleterious substances which may be present in the atmosphere. Thecabinet is denoted generically as 6 and has drum supporting means asdescribed in FIGS. 1l, l2 and 13 mounted therein. The cabinet shouldhave a door or removable panel large enough to allow swinging the drumto the positions indicated in FIGS. 11 and 13.

The limit switches and the homing switch, generically denoted as 4 and 5in FIG. 2, are mounted from a switch supporting bar S which is supportedwithin the cabinet. Brackets 1t), 11 extend from each side of the bar 8in a direction generally perpendicular to the axis of the drum 2. Thelimit switches (actually H1, H2, L1, L2 but referred to as 4 and 5) 4and 5 are secured in the respective brackets by any suitable means suchas glue, screws 14, 15, or the like in such a position that their pinengaging members 16 (ordinarily a roller in accordance with limit switchand micro-switch construction) is aligned with the pin engaging memberof all other limit switches regardless of which side of the bar 8 theyare mounted The drum 2 is a hollow cylindrical perforate member withholes located as shown for axial and peripheral alignment.

The support bar S may advantageously be hollow and perforated along thesides from which the limit switches are supported. In this fashion,wires or other electrical conduit means can be led to the respectiveswitches through the hollow portion of the support member 8.

As shown in FIG. 2, the pins P have a T shaped cross section with a stem18 and a head 19. The pins a-re ref movably mounted in the drum bydriving the stems into the perforations 3@ which are arranged in rowsboth axial and peripheral of the drum 2. The heads of the pins areshaped so that the pins may be positioned adjacent each other in aperipheral drum row so that they 6:50? engage and maintain engaged alimit switch on two successive steps of the drum.

In one embodiment, described hereafter with reference to FIGS. 3 and 3A,the driving means is arranged to step the drum through 60 increments of6 each in one Of course, other arrangements for stepping may beemployed, but this is convenient because minutes and hours both have 60seconds and minutes, respectively, and the drum is thus automaticallydivided 755 intervals encens? FIGURES 3 and 3A FlG. 3 shows in crosssection the arrangement of the drum motor Ztl, the dead centering means2d, and the gear train 22. The v/hole is arranged so that the drum Z maybe easily removed and so that the motor and gear train is encased withinthe drum.

Referring now to FIG. 3, there are shown the drum ZZ secured byremovable means such as a plurality of screws to a pair of hubs 52, 5dwhich are spaced apart along a non-revolvable shaft S. The shaft has aflatted portion 5d to which the motor 2t) is secured by any suitablemeans such as screws, brackets, or the like. The shaft has a hollowportion 6@ preferably disposed at the inboard end adjacent the hingemeans for swinging the drum out of the bracket to change drums andthereby installa new program, Wires for the motor 2d and various switchmeans associated with the dead centering means are led in to the insideportion of the drum through the hollow portion 6d.

The hub 54 is revolvably mounted on the shaft 56 by any suitablebearing, prefera ly a frictionless bearing such as a ball bearing,indicated generically as 62. Hub is maintained in its position on theshaft by a pair of spaced apart rings o3, ed which are secured to theshaft by set screws do' and e6.

rlhe hub 52 is mounted in a partly similar fashion, but uses ti e geartrain 22 and the supports thereof in lieu of a ring such as 63 to guardagainst axial displacement to ward the other hub.

The gear train is supported from the shaft by support means genericallydenoted as id which is secured to the shaft and so constructed as toallow various portions of the gear train to revolve relative both to thesupport means and the shaft 56. The support means (and the gear trainfor that matter) is secured to the shaft by a pair of spaced apart geartrain supporting hubs 7l, 72 which are respectively secured to the shaftby set screws 73, 7d. A plurality of washers '75 are disposed betweenthe support hubs and adjacent revolving members, one of such washersbeing used to space the drum hub 52 from the support 7l.

An idler support plate 77 is secured to the hub 7i by any suitable meanssuch as screws, Welding, or may be formed integrally therewith. A deadcentering switch f support plate 7d is supported in spaced apartrelation to has an aperture 33 through which the motor output;

shaft 2l extends.

The motor output shaft is connected directly into the gear train bymeans of a Geneva wheel arrangement which includes a Geneva pin wheel 34having in the preferred Y embodiment a pair of spaced apart pins 35secured thereto by any suitable means such as force fitting, weldin g,or the like. The reason a pair of pins is used is that the Geneva wheel3:5 is a tenpoint drive having ten slots therein.

The dead centering timing wheel lll is formed as a plate mounted torotate in unison with the Geneva pin wheel.

A sleeve 87 is disposed between the Geneva wheel and a shaft mountedgear Sil in such fashion that the gear and Geneva wheel rotate together.Appropriate bearing means 89 are provided to revolvably support from theshaft the Geneva wheel, gear and sleeve. With this construction, thegear 8S and the Geneva wheel S6 rotate in unison.

A driven drum gear gli is secured to the hub S2 by any convenient meanssuch as keying or a forced fit in order that hte drum rotate in unisonwith the gear 9). A pair of idler gears 9i., 92 connect the gear 83 tothe gear 9). The idler gears ar-e revolvably supported from the supportmeans 76, preferably from a single shaft 93 to which they are bothsecured to rotate in unison. The securing means may advantageouslycomprise idler set screws 94 which engage fla-tte-d portions on theshaft 93.

The shaft 93 is revolvably supported by a pair of bearings 95, 95. rEheidler shaft bearings 95, 96 are respectively supported in the idlersupport plate '77 and the switch support plate 73. The bearings mayconveniently be shaped as bushings so that the idler gear 92 ismaintained in axial alignment with its mating gear S3.

ln review, as the motor 20 rotates, the Geneva pins 35 rive the Genevawheel Se which revolves in characteristie intermittent Geneva fashionand causes gear 38 to move in like fashion. Idler 92 is supported inmeshing engagement with gear and responds to the motion, transmitting itto the idler gear @l which then, being in mesh with the drum gear 9d,drives the latter. Thus, a speed reduction is obtained at the same timethe requisite intermittent motion for obtaining a stepping action isprovided. ln the preferred embodiment, it is desired to step the drumone 6 increment of rotation in response to a lSO" rotation of the motor.Thus, a 3G to ll reduction is preferably provided. Consistent with this,the holes for receiving the various pins are spaced at 6 intervalsaround the periphery ofthe drum.

When it is desired to remove the drum and replace it with one having adifferent program, the screws 5t) are emoved and the drum moved axiallyuntil it is free of the hubs.

ln the upper central part of PEG. 3 is shown a detent mechanism formechanically positioning the drum and the motor at dead center. Thiscomprises a detent ball 97 which is mounted in a hole at the end of anexternally threaded hollow detent case 93 which is screwed into acorresponding threaded hole in the motor support plate ft2. A detentlock nut 99 further secures the detent assembly in place.

Although not shown, the hollow detent case contains a compressed helicalspring which biases the detent ball 919 into frictional engagement withthe face of the Geneva pin wheel 84. If desired, small depressions canbe formed at dead center position in the face of Geneva pin wheel 84,which depressions are engaged at the end of rotation by the detent ball.

FIG. 3A illustrates a cross sectional view taken along line 25A-3Alooking in the direction of the arrows, of FIG. 3 and shows in whatposition the dead centering switch 108, R07 is secured relative to thedead centering wheel 111. The dead centering switch is screwed to theswitch support plate 73 by a pair of screws 78a `and 78h. The arm 1M ofthe dead centering switch is thereby positioned with respect to the deadcentering wheel 111 so that switch Mld is closed when off dead centerand open at dead center as elsewhere described in greater detail. Theswitch 10S, M7 may be any commercially available type of microswitch.

The timing wheel lll in the preferred embodimeint is different in minordetails from that shown schematically in FIG. 4, principally in thatlobes M2' and lf3 are provided in lieu of the notches 112, 113 shown inFIG. 4. It will be observed in FIG. 3 that the Geneva drive pins '85 arespaced apart so that one is entering a Geneva slot slot. This furtherpromotes positive positioning. Dead center is preferably arranged sothat the pins 85 are in the positions shown in FiG. 3A when at deadcenter. rIbis permits the driving pin S5 which is entering the slot topromote a stepping operation having a low initial and final rotationalvelocity, with a high intermediate velocity to get a sharp break incontrol functions, (ie. break occurs during intermediate). When thedriving pins are positioned as shown in FIG. 3A, (ie. deadcenter) thedrum is also at dead-center. The phrase dead-centering refers to thedrum as well as the motor inso-muchas the two are connected by virtue ofthe Gencval wheel and related gearing.

introductory description of discrete interval embodiment (FIGS. 4, 5, 8and 9) rfhe operation and construction of the discrete intervalembodiment is best understood by reference to FIGS. 4 and 5. Althoughdirect current in the form of batteries is shown for example as thepower source in some instances, it is to be understood that eitheralternating or direct current may be used. However, it is preferablethat alternating current may be used. Direct current power sources areshown in the form of batteries 162.

FIG. 4 shows a memory device or drum 2 having a plurality of pins 4mounted thereon in the fashion of FG. l, described above. In theexploded portion, an electrical motor 20 drives the drum through a geartransmission assembly and mounted on the motor shaft to rotate in unisonwith the motor in a dead centering means 24.

A plurality of timers 1M, generically, are connected in parallel betweenthe power supply and the ground. A timer selection means 195 (L3, L4 inFIGS. 5 and 8) is associated with each timer, being connected in seriesbetween the timer and power supply arranged to enable one timer anddisable all other timers. The selector switches are actuated by the pins4 on the drum. A timer enabling switch 1li? is ganged with the deadcentering switch 163 so that each is disposed between the power supplyon one hand and, respectively, the timer selection switches 136 and thedrum motor, respectively.

Stated broadly, the mode of operation of the discrete intervalembodiment contemplates that each of the interval timers 1134 is set fordilerent lengths of time. rEhe pins on the drum are arranged to selectone timer while disabling all the others at each step of operation. Thesystem is so arranged that the drum motor 2t) cannot operate while anyone of the interval timers is running and so that the interval timerscannot operate until the motor Ztl has reached a predetermined motorposition. The dead centering means denoted generically as 24 enables themotor 2t) and the selected one of the interval timers to operatealternately but never simultaneously.

Assume the system has been properly started and is in operation,referring to FIG. 4. Also assume that the drum or memory device 2 hasbeen stopped at the position shown in FIG. 4. The pin P3 engages theleft hand timer selection switch d causing the left hand timer to beginoperation. The entire system stands still for the particular discreteinterval for which the left hand timer is set. rThis may be, forexample, thirty seconds, live minutes, fifteen minutes, or any desiredquantity since the timers are adjustable. During the time interval, asthe timer runs the timer arm 110 approaches the timer contact arm 169and thereby completes a circuit from the power supply to the motor 26'.

The motor responds by starting to turn and in doing so the timerenabling switch 1117 is opened thereby preventing any of the timers fromoperating until the switch is closed, and permits the spring to resetcontact arm 169 (i.e. open circuit to motor 20). With the arrangementshown, the switch does not close again until the motor has rotated 180.At the same time that 197 is opened, the switch 168 is closed andthereby establishes 10 another circuit from the power supply to themotor: the circuit thus established enables the motor to drive until itreaches dead center away, at which time the switch 108 is opened.

When the motor has driven through 180 and reached its predeterminedposition, the operation is again repeated with license to select adifferent timer, the other steps remaining the same.

For purposes of explanation, the dead centering switch and timerenabling switch 10S, 107, are shown as actuated by a timing wheel 111having timing notches 112, 113 180 apart to actuate the switch arm 114.A more detailed embodiment will be described below with respect to thedetails of FIGS. 1-3.

It will be appreciated that a control function such as opening a Valveand maintaining it open is carried out during the time that the drum 2is at rest. The length of time that the drum is at rest, or dwells, isdetermined by the interval timer and therefore the particular controlfunction to ultimately be carried out is determined on a time basis.

A more detailed explanation, including the structure and operationrequired for starting, skipping and holding is set forth below ingreater detail with reference to FIGS. 5, 8 and 9. As will be seen, morethan two timers may be employed and more than one particular controlprogram can be stored 0n the drum 2.

Introductory description of FIG. 8

The circuit of FIG. 8 is arranged so that it can be used either with thecircuit of FIG. 9 or with the circuit of FIG. 10. As will be explainedbelow, when FIG. 8 is connected with one of FIGS. 9 and l0, thearrangements of FIGS. 4 and 6, respectively results. The system of FIG.8 may also be arranged for manual operation. FIG. 8 is shown set up forautomatic operation in conjunction with the circuit of FIG. 10. Manuallyoperated selector switches 146, 147 are used to set the system of FIG. Sfor either manual or automatic operation. Automatic operation meansautomatic stepping in conjunction with one of the systems of FIGS. 9 or10. Switches 146, 147 are shown positioned for automatic operation.Manually operated switches 148, 149 are used respectively for manuallystepping or for manually rotating the motor 2t), and during setupoperation.

Manually operated cycle selector switches 150, 154 are used to set thesystem of FIG. 8 for use with either the system of FIG. 9, or that ofFIG. 10. As shown, cycle switches 150, 154 are set for use with the FIG.10 system through engagement with their respective contacts 151, 155.The cycle switches 159, 154, are moved against their respective contacts152, 156 when it is desired to use the FIG. 8 system in conjunction withthat of FIG. 9.

The system of FlG. 8 also includes timer enabling switch 167 and deadcentering switch 163 which are, respectively, normally closed andnormally open at motor Ztl dead center. Switches 167 and 163 are,respectively open and closed when the motor is o-Fr" dead center, e.g.when the motor is running. Dead center is where the motor should beafter the drum has been stepped to a proper predetermined position.

A terminal block is provided having terminal blocl: connections T131 toTB17. rl`hese terminal block connections are identical to those shown inFIGS. 9 and 10. The power supply 1% is connected to the system through apower switch 15S, which latter is always closed before the system is putinto operation.

Program master switches L1 and L2 are connected between the terminalblock and switch 147. Discrete nterval timer selection and alternativeprogram master switches L3 and L4 (1136 in FIG. 4) are connected betweentheir terminals and cycle switch 159. In the preferred embodimentswitches L3 and L4 are ganged t0 additional switches LS-2 and L4-2 bothof which latter are normally closed and connected in series with eachother between the terminal and switch An alternative embodiment denotedas 266 is illustrated in FlG. 5l).

For convenience later on, it is to be observed that the switch numbersLl Ld all correspond to a row of pins on the drum so that Ll correspondsto Pl, L2 to P2, and so forth.

Ganged ho-. ing switches H-l and HZ, operate-d by honiing pin HP areprovided. Hl is open at home, closed during running (drum oliF home). HZis closed at hon-1e and open when the drum is ol home (le. during aprogram).

A relay Rl is provided having a plurality of contacts Rll, Rleach ofwhich contacts is norma y open and connected in series between the powersup y and a controlled function switch L5, Le The controlled functionswitches L5, Le each correspond to a row of pins on the drum such aslle', P6 lt is to be understood that any number of contacts Rl--l etc.any number of function str/ches L5 etc. may be provided. Ordinar-illy,the function switch controls some process step by operating anelectrical device, shown by way of example as solenoids and Thesolenoids may operate a valve, a switch, or like. lt is to be understoodthat the thing controlled, represented by the various solenoids, may beany suitable means for achievthe desired control function. A pluralityof sig Aal lights lol, E62 and ia are provided for convenience indetermining it various circuits are operating. The switches L3 and L@ ofPEG. 8 correspond to the swi. es ldd of FIG. 4 as indicated by the numers in parentheses. As described with more particular reference in FlG.5, the switches L3 and Lft are employed for selecting a imer While theswitches Lil and L2 are employed as a master programming switch. Asexplained elsewhere with reference to the con'guration of pins on thedrum, it will be observed that at least one ot the switches Ll Lft hasto be closed by a nin and one of the switches L5, L5 has to be closed byan axially aligned pin in order to achieve a control function. Where thesystem of FIG, 9 for stepping with discrete intervals is employed, it isfurther required that a third pin on the drum be aligned so that one ofthe switches L3 and L4- is closed at the same time one ol the other twois closed.

introductory description of FIG. 9

ln the embodiment of PEG. 9, power is brought in through the powersupply of Fifi. 8, through terminal Z past a normally closed manuallyope 'ated emergency stop switch l7ll to a starting Circuit genericallydenoted JZ. rEhe starting circuit is connected across the power supplybetween leads from terminals TBE and A plurality of timers (see iG. 4)are connected between terminal TBll and respective terminal bloclrsshown here as blocks TBS, rl`B7 and TES, The timer operated Contact armsgenerically denoted as E99 (FlG. 4) are connected in parallel with eachother between the starting switch and terminal TRES.

As an optional feature a n anually operated stepping switch 74 isprovided in parallel with the timer switches N9. Switch l is no niallyopen. An automatic selector switch Tir/'6, similar function to switchesldd, ld? of FlG. S, is provided to connect between terminal TBE-6 andthe block of timer operated switches Selective switch l'i is shown inthe position required for automatic stepping operation. lf desired tomanually operate the system oi FG. 9, when connected with HG. 8, switchl'd is moved against Contact 77 to place it in series with the normallyopen nanually operated rotatin switch i7@ which la ter is connected tothe lead is connected to the starting switch. A second auto i". selectorswitch is shown connected between termina T29 and the start joggingrelay The switch llZ is shown closed for automatic stepping operationswhen FlGS. 8 and 9 are operating,y as one system: in order to put thesystem on manual operation the switch i893 must be opened and the switch175 moved against Contact i7?.

For corn/enitv switches and 76 may be The relay man' 11atcs a set olnormally closed witch contacts R -v wA ich are connected in parallelwith the timer operated itches lll?.

A manually operated program selector switch i.l provided to connectbetwee the lead and a selectet one of the program master switches Ll andThis permits storing two programs on each drum, the master switch Llcontrolling one and the other program being controlled by L2. Theparticular program on which the system is to be operated is selected bypositioning the switch here shown as selecting t` e program dened by themaster switch Ll by connecting the master switch to tie lead ce comingout of the starting circuit i272.

Leads il and 18? (FlG. 9) serve to connect the horning switch (FG. 8) inseries between the starting circuit 172 the starting circuit The resetcircuit (PEG. 9) includes a resetting or holding relay R2 which whenenergized changes the state o the respectively normally open closed s'itches RC3-2 and Rfid; and includes manually operated resetting switcwhich is normally open connected in series between the homing switch Hl.and reset relay R5. The reset relay R5 controis the normally closedcontacts R5 which are in series between the starting switch and theprogram selector ""3 also controls the normally open switch which is inparallel with the lll .ual switch As as operation ot' the system isordinary and normal, the manual reset por ion of is not empl. jed. lt isordinarily employed to malte a justnients without the danger of startingthe various control functions.

A plurality of signal 'im are provided as desired to denote variousconditions ol the system during operation and when at rest.

The operation ol: the starting circ it 1'2"?, will be b r understoodwhe. a description of the operating and starting functions of the F 8and 9 system is given. the present, it should be observed that the star'I J2 includes a system starting switch connected in series with aconvenient starting relay r2. across a norrnaily closed switch R-l whichis manipulated by the relay R3. A normally open Contact RZ-l iscontrolled by relay RZ, the former being connected in parallel with thesystem switch A normally open switch R-Z is also connected in parallelwith the system switch and is riunioulated by relay R3. The relay R2 isprovided so the operator will not have to hold the system switch Zilliclosed until operation has gotten well under way and for trat reason isa convenience relay. The relay R3 is used to stop the motor and drum atthe home position, as elsewhere described.

A plurality of individual timers Tl., .d are included in the group oltimers itil-i in FlG. Preferably, each of these timers is constructedalike except each is adjusted so that it provides a dil'licrent discretetime interval than any of the others.

These tir .ers are conveniently adjustable. The construction oit onlyone timer will be described, it being understood that the remainder areconstructed in similar fashion. Each conventional ti ier includes aclutch solenoid 232, a timer motor 2 a timer stop switching assembly(which may be a relay) Tt-l and a m motor starting switch "fi-2;. TimersT2 and T3 also have their respective drum motor starting switches TIFZ aas shown generically by reerence number These timers are of well knownconventional construction. Each timer resets itself automatically afterit has run for a discrete time interval. Although one type of timerconstruction is shown and described, any kind of conventional timer maybe used as long as it automatically resets. Preferably, each timer isadjustable for discrete time intervals over a range, whereby one suchdiscrete interval is selected for each timer for each program, all aswell known in the art.

13 Operation of the system of FIGS. 8 and 9 (sce also FIGS. 4 and 5)Before the system is started, for automatic operation, the switches 146,147, 176 and 1%2 are all moved to the positions shown. Then the cycleselector switches 150, 154i are moved to engage their respectiveterminals 152., 156 and the program selector switch 185' is moved toselect the particular program, shown as that controlled by pin P1 andthe switch L1 for purposes of explanation. Also, the two homing switchesH1 and H2. are adjusted so that H1 is always open when the system is athome and that H2 is always closed when the system is at home. The homingpin HP on the drum operates switches II1 and H2 which are convenientlyganged together. The switches H1 and H2 are shown in their positionduring the running portion of the cycle for future convenience. Thesystem switch 200 is closed by the operator, and as with switches ofthis nature it very shortly returns to its open position. Relay R2 isactuated responsive to this and closes the contacts 122-1. Closing thesystem switch also applies power through lead 180 across normally closedcontacts R41-1 to the motor 20 which then moves out of the home positionand thereby closes homing switch H1, simultaneously opening switch H2.

Closing of switch H1 completes a circuit to the holding relay R3 vialeads 186, 187. The holding relay then shuts oil the convenience relayR2. by opening contacts R3-1 and establishes a power supply by closingcontacts R32. It is assumed that the switch 15S has been closed toprovide power.

The motor now drives the system until the rst pin P1 engages itscorresponding switch L1. The drum even drives past its dead center anypredetermined number of times to allow this to occur. The operation ofdriving past dead center is termed skipping and is more readilyunderstood by reference to FIG. 5 where it is seen that a circuit iscomplete to the motor across the switch R4-1 motor runs and while it isolf dead center, the dead cenas long as switch L1 has not been closed.While the tering switch S is closed. The dead centering switch onlycomes open at dead center for reasons best understood by reference toFIG. 4. In FIG. 4, as well as in FIGS. l-3, it is to be observed thatthe timing wheel 111 manipulates the dead centering switch 108 to keepthe latter closed at selected times while the motor is away from deadcenter. This is achieved by proper positioning of the means foractuating dead centering switch, which means are shown as the notches112 and 113 in FIG. 4 but may also comprise the lobes of timing cams asdescribed with reference to FIGS. 1 3.

The motor drives the drum through the skipping operation until the firstoccurring pin P1 closes switch L1, thereby actuating relay R4 andopening the contacts Rd-l. Ordinarily this occurs slightly ahead of thedead centering position, as does opening of the dead centering switch103 whereby the motor inertia allows motor 2li to coast to dead center.

Referring now to all FIGS. 5, 8, and 9, when the motor has arrived atits rst dead center position the switch 103 is open. There are at thistime no circuits cornpleted from starting circuit 172 to the motor.However, the timer enabling switch 107 has closed and the pin P3 hasclosed one of the timer selection switches 106, it being assumed thatthe particular switch closed is L3. The means 104, 109 assume that allother timers are disabled and cannot run. A cir-cuit is then completedthrough L3 and 107 to timer T1. (See FIGS. 8 and 9, TB 6.) This startsthe timer running at the very instant the motor 20 has stopped at itsdead center. Of course, any other timer selection means such as L4, L4-2and L3-2, or L20 (FIG. 5D, explained below) can start its associatedtimer and leave all other timers disabled.

The timer runs for its predetermined time interval and, as heretoforedescribed, shuts itself ofiC (by opening switch 14 'I1-1) and closesswitch T-Z to thereby start the motor 20 again. When the motor moves offdead center, the timer automatically resets itself in accordance withits own internal construction and the motor drives to the next positionand selects one of the timers, repeating the stepping operation.

If there is no pin in row P1, the switch L1 comes open if there is nopin in the corresponding row. This allows the contacts R4-1 to close andthereby a skipping operation occurs past any predetermined number ofdead center positions until the next pin occurs to close switch L1 atwhich time occurs the above described sequence of dead centering,enabling the timer via the timer selection switch such as L3 or L4, andthen starting the timer via closing switch 107.

A similar procedure occurs if program selector switch is connected toterminal TBS whereby pins P2 via swtiches L2 operate in the fashiondescribed for P1 and L1.

As previously stated, this procedure assures that the motor 20 does notoperate while the timer is running and that the timer cannot start untilthe motor has reached dead center. This is because of the cooperationbetween the two switches 107, 108 and the fact that the pins on the drumset up the timer circuits through L1 and L3 to put the switch 107 incontrol of the situation while the motor is dead centering.

As best seen in FIG. 5, at the same time the switch L1 is closed by apin, relay R1 (FIG. 8) is actuated so that its various contacts Rl-l,R1-2 are closed to complete circuits to the respective control functionswitches L5, L6 If a pin is arranged on the drum to engage and close oneor more of switches LS, L6 then a control function is initiated. Whenthere is no pin on the drum, the control function is terminated. In theembodiment shown, there have to be three pins aligned axially on thedrum to achieve a control function, with certaink exceptions asexplained later. The three pins which have to be aligned are: one of theprogram switches L1, L2 (in this embodiment), one of the timer selectionswitches L3 or L4, and one of the control function switches L5 Ofcourse, more than one control function may be obtained at the same timewhich merely requires aligning more pins axially in the P5, P6 rows ofpins on the drum.

After the drum has stepped and skipped, as the case may be, through itscomplete cycle of controlling functions, it then must home by bringingthe motor to dead center with the homing pin H engaging the homingswitches to open switch H1 and close switch H2 (see FIGS. 8 and 9). Whenthe motor starts to home there are no more pins to maintain switch L1closed and therefore contacts R44 close and drive the motor as withskipping. When the homing pin engages switch H1, it breaks the circuitextending from the starting switch to the holding coil R3 which thenreturns R3-1 and R3-2 to the position shown in FIG. 9, thereby shuttingoff all power to the motors. Thus, when the motor drives the drum tohome position, the homing pin serves as a means for stopping the motorat the predetermined homing position by shutting olf all power to themotor.

When the motor has homed, the various switching connections between thestarting circuit 172 and the motor 20 are in substantially the positionshown in FIG. 5. Observe that when the last pin P1 has passed and themotor starts its homing function, the relay R1 shuts olic all current tothe control function switches by opening the contacts R-l and R1-2.Thus, there are no controlled functions during homing.

The embodiments of FIGS. 5A, 5B, 5C and 5D These embodiments showvariations in the system of FIG. 5. For convenience those portions ofFIG. 5 which remain the same are omitted.

FIGS. SA, 5B, and 5C are all concerned with means for interrupting thetime interval basis of stepping by FG lo d' crete intervals. Theinterruptions are or such nature as to either lengthen or shorten thetime intervals in response to some event in the control cycle other thantime. This event may be the achievement of a redetermined pressure,temperature, velocity, weight, or chemical composition in the systembeing controlled. Suitable means such as recorder Controllers may beemployed in these embodiments.

PEG. D represents a modihcation of the FIG. 5 means lid? for selecting atimer.

FGURE 5A The embodiment of FIG. 5A sh ws that portion of the circuit or"FlG. 5 which has been modified to either lengthen or shorten the timeinterval of a dwell period by some control signal other than time.Examples of such control signals are chemical composition as drawn froman infra red or ultra violet recorder controller, r'iow, velocity,pressure, temperature, to cite a few by way of example but notlimitation.

The modiiications in FIG. 5A include elements 2553 and Both or theseelements represent some control signal source for closing a switch. Thecontrol signal source may be assumed as a recorder controller or anyother suitable means.

A means for interrupting the timer operation to lengt the time of dwell,that is to increase the length of time that the drum is held at oneparticular position, is indicated by the means Assuming this to be, forexample, a pressure response means, wherein it is desired to continue acontrol function until a certain pressure reaches a predetermined level,the means will close its switch 252. when that level is reached. Untilthat time, the switch 2552 is open and therefore, regardless of whetherone or more of the timers has closed its corresponding motor startingswitch Tit-2, "lf2-2 the motor will not start until such time as theswitch 252 is closed.

if it be desired to shorten the length of time responsive to a signal,let us maire the same assumptions as before so that when the pressurereaches a predetermined level the means 26@ closes the time delay switch252. Means Edil and switch 2&2 are constructed for mal;- in g rapidlyand breaking after a delay. Closure of switch starts the motor Ztl andcauses a stepping operation as before. The time delay of means 26) andswitch 262 is such that the switch breaks the circuit before the motorreaches dead center, whereby the dead center switch lil@ stops the drummovement.

FIGURE 5B The modification of FG. 5B illustrates a system generallysimilar to that of FlG. 5A whereby individual timer control circuits forstarting the motor have their respective time intervals lengthened in anindividual fashion. This permits one or more time intervals to belengthened in response to respectively different control signals.

FlG. 5B shows time interval lengthening means such as switches 252s,252i), and 252C, respectively, in series with a timer controlled motorstarting switch Tir-2, TZ-Z, and 'lf3-Q.. Each of the time lengtheningswitches 252e may be responsive to a different event requiringengthening of the time interval. Thus, switch 252a may be responsive toa predetermined pressure while switch 252!) may be responsive to apredetermined weight, and 252e may be responsive to a predeterminedtemperature. The signal for operating each of switches 2520, 2526 252emay be drawn from sources such as 25d, 26H3 of FlG. 5A.

FUURES 5C and 5D FIG. 5C shows an embodiment whereby the interruptingmeans can be programmed into the system so that it is disabled except atpredetermined times which are selected by the function switches L5, Ledescribed iti FIG. 8. 5C is generally like FIG. 5 except for the portionshown which includes the interrupting switch Z'x and the interruptionselector switch Euring operation the drum rotates and closes the switchZodwhcreupon the interrupting means 25) can, upon command, close theswitch 262x thereby shortening the time interval.

A further modilication would include means for selecting a timelengthening function which would involve connecting a normally closedswitch in parallel with switch 2523 of FIG. 5A. When desired tointerrupt the time basis of stepping, the paralleled switch is openedthereby putting switch 2d?. in command. The paralleled switch isoperated by one of the pins on the drum and corresponds with one or theswitches L5 FEG. 5D shows a modification for selecting one of the timersTl., T2 or T3. A comparison with FIG. 5 is in order at this time. Whenselecting one of the timers in FIG. 5, one of the switches L3 or L4 isclosed to select its timer. ln doing so a ganged switch E43-2 or L4-2 ofFlG. 8 opens to disable the third one of the timers. ln this lash n onlytwo selector switches L3, Ld have to be used. Similar arrangements maybe employed so that you have one less row of pins on the drum to selecta timer than you have timers. With the embodiment of FlG. 5 the thirdtimer is selected when there is no pin at all present to actuateswitches L3 or Ld.

in FIG. 5D there has to be a pin on the drum to close the appropriateone of the switches L3, Ld L29. Each of the timer selection switchesstarts its own timer. With this embodiment the number of timer selectionswitches and rows of pins corresponds to the number of timers used.

Introductory description of non-discrete interval embodiment (FIGS. 6,7, 8, and 10) PEG, 6 shows in skeleton detail certain characteristics ofthis embodiment. lt will be observed that the drum, gear drive, deadcentering means, and motor are arranged in generally the same fashion asdescribed with reference to FIG. 4. A pulse source l2@ provides startingpulses to the drum motor through a pulse source control switch 122., astart positioning means Zfi, and a stepping control and reset meansi226. The dead centering switch lili; is in the circuit and continues toserve as a means for stopping the motor after it has arrived at itspredetermined position, i.e. for stopping the motor after it has movedsufficiently to execute one step of the drum. rthe remainder of thecircuit is provided to enable the drum to start in response to pulsesfrom the pulse source so that the switch N8 can complete the circuitthrough itself from the power supply liti?, to the motor. The means 26is arranged, as described below with reference to FIGS. 7, 8, and l0, toreset itself responsive to the ending of a pulse from the pulse source.Thus, the pulses are long enough on a time base so that the motor canstep once, the resetting taking place after the motor has stepped. ltwill be observed that there is a row of pins Pi arranged consecutivelyaround the periphery. Tre row Pl assures that the circuit through 122.is maintained for the particular period of the control program indicatedby the peripheral length oi ln the presently preferred embodiment, thepulse source contemplates a plurality of iight sources 13o, lill. Acorresponding plurality of photo/electric cells l?, 133 is arranged onthe other side of a light beam chopping disc l which is driven by a dialtiming motor l36. The disc T135 has a plurality of slots E37' arrangedtherein. The slots are arranged in annular or circular rows so that oneentire circular row comprises one program. An elongated homing slot l'is provided Jfor purposes which will be explained with reference to thehoming operation n FlGS. 8 and l).

Each disc Il35 may include a large number of programs, each occupyingits own annular ring of slots. As the disc is rotated, the slotsestablish a light beam from the source 130 to the photoelectric cell132. The beam continues to exist for a length of time required for theslot 137 to pass between the light source and photo cell. This length oftime should exceed that required for the motor 20 to step and stopresponsive to the dead centering switch 108.

Each disc 135 ordinarily has a large number of programs stored thereon.Each program occupies its own annular circular track or path. With theembodiment shown, transient light from one light source may causeseveral of the photoelectric cells to produce pulses simultaneously.This occurs in random fashion and, if not controlled, serves to confusethe system and cause the drum to be stepped where stepping is not partof the program set forth in the slots on the disc.

The ganged selector switches 139, 14@ serve to eliminate this transientlight. Before operation the selector switches are moved to the positionsshown, thereby selecting the program indicated by the outermost row ofslots 137. This program corresponds to that indicated and aligned withthe pin row P1. The selector switches turn on only one light andestablishes circuit from only one photocell to the start positioningmeans 1.24. In the embodiment shown, light 130 and photoelectric cell132 have been placed in circuit.

Operation is believed to be evident from lthe foregoing. Briey, however,it is to be understood that the selector switches are first put inposition and when the starting system is closed, the system moves fromits home position to a zero time position at which time the drum issynchronized with the first slot on the timing disc. Thereafter,operation requires merely rotation of the disc to intermittentlyestablish light means in some predetermined fashion. Each time a beam isestablished between the light source and a cell a pulse is generatedwhich causes the motor 20 to move ott dead center and to drive to thenext dead center position where it stops in response to switch 108breaking the circuit. The light pulse then stops as the disc interposesitself between the source 130 and the cell 132, whereupon the resetportion of means 126 prepares itself to receive the next pulse. It is tobe observed that the time interval for effecting a control function isrealized by the length of time between the slots 137 and whateverprogram is selected on thel disc.

Appropriate circuitry for describing in detail the responses to thepulses during running, as well as for starting and homing, will bedescribed below with reference to FIGS. 7, 8 and 10.

Inlioductory description the embodiment 0f FIG. 10

The circuit of FIG. l0 is used in conjunction with the circuit of FIG.8, assuming that the various manually operated switches are set in thepositions shown in FIG. 8 and that switch 158 is closed. This allowsthere to be four programs stored on the drum or on the disc, or on bothas the case may be, as indicated by the switch arrangement of FIG. 8 andalso by there being four light sources 130, 130', 131, 131 and fourphotoelectric cells 132, 132', 133, and 133 in FIG. l0. As evident bycomparison of FIGS. 6 and l0, any suitable number of programs may beprovided for in accordance with the number of lights, cells, annularrings of slots on the disc, and the like. In the embodiment shown inFIGS. 8 and 9 four programs are allowed and accordingly the selectorswitch 185 of FIG. l0 is provided with four contacts for selecting oneof the four programs. In the embodiment shown, it is assumed that theprogram controlled by the master switch L1 is selected.

Referring now to FIG. l0, a manual function switch 219 -is provided andis closed anytime the circuit is to be placed in operation. A pluralityof signal lights 193', 196, 194 and 1% are provided as desired.Similarly, a

manually operated reset circuit including the normally open switch 190and relay R5 are included, serving the same purposes as in FIG. 9. Thevarious elements of the stepping control and automatic reset means 126(FIG. 6) are shown as are the portions of the start positioning means124. The elements 124 and 126 will presently be described in detail. Astarting circuit 220 receives power from terminal TB2 and by means ofthe holding circuit is used to start and maintain the system inoperation until the starting circuit itself is disabled responsive tothe motor 2i) having driven the drum to a home position. Although notshown in FIG. 6, a homing motor 222 is provided so the disc can berapidly driven to home position once a given program has been completed.Thus, there are two motors, the ordinarily slow operating electric motor136 for driving the disc 135 through a program and the homing motor 222,all in addition to the drum motor 2?.

A homing light HL and the homing cell HC are provided for cooperationwith the homing slot 13S in the light chopping disc 135.

A transformer 224 receives power through the starting circuit 220 andapplies to a photoelectric cell ampliiier 226 which latter receivessignals from a selected one of the light cells, amplifies it, and thenactuates a relay RL. Thus, there is provided a means for responding to abeam of light admitted through one of the slots 137 to thereby cause thedrum motor to step responsive to such light.

The system of FIG. l0 is arranged to cooperate with FIG. 8 so that aparticular program may be selected and when the system is started, boththe drum motor 20 and the dial timing motor 136 are'brought intosynchronization on a time base so that the drum is positioned inaccordance with the disc 135. More specifically, the system is arrangedso that the drum motor starts in response to a beam of light and drivesone step to dead center, after which the beam of lights cuts off andresets the system for the next operation. The details of this aredescribed below but attention is now directed to the relay RL and itsnormally opened contacts RL-l. The starting procedure and thecooperation of the elements of FIG. 10 are so arranged that RL-l startsthe motor 20 when a beam of light strikes the light cell 132. Relay RLalso controls two other contacts, normally open switch RL3 and normallyclosed switch RL-Z.

Returning for a moment to the starting .circuit 220, a master switch 230is connected across the power supply and in series with homing switchHe2. A convenience relay R-11 responds to closure of the master switchby actuating the holding relay R12 which latter is connected in serieswith homing switch H1. In doing so, R11 changes the state of normallyopen contacts R11-1 and R11-2 until the motor is moved on home positionthereby opening contact H-2 to disable relay R11 and closing switch H1to thereby enable the holding coil R12 during the course of the entireprogram and until the drum has been returned to home. It will beobserved that the reset relay R5 had additional contacts R5-2, RS-S andR541, the latter two being normally closed.

The power supply to the -t-iming disc motor 136, the homing disc motor222 and the pulse source (FIG. 6), 228 (FIG. 10) is independent of thestarting circuit. The homing function of the pulse source is thusindependent, in a fashion, of the drum.

The starting positioning means 124 as arranged in FIG. 10 is dividedinto two portions 124a and 12417. A plurality of parallel connectedrelays R14, R15, and R16 are disposed in the means 124e and connected toterminal 9 thence to the selector switch 185 and one of `the pinswitches, e.g. L1 (or L4). Relay R14 is provided to turn on the motor136 at an appropriate time and, during homing operation, to turn on thehoming motor 222, by manipulating contacts R14-1 and R14-2. kThe timingmotor is operated during starting and homing and by normally closedcontact R14-3.

Relay R manipulates switches R15-1 and R15-2 to thereby select thesource of input signals to the pulse source amplifier 225. Normally opencontact R15-1 channels signals from the selector switch 140 whilenormally closed contact R15-2 ychannels signals from the homing cell inthe amplifier. Relay R15 also controls a portion of the circuit 124a bymanipulating switches R15-3 and R15-4.

Relays R16 and R17 are a push-pull type of relay which control theircontacts so that one is engaged and one is disengaged and so that ittakes two signals applied tirst to one relay R16 and then to the otherrelay R17 to move the contacts out and then return them to their initialposition. In other words, when the contacts R17-1 are closed, those atR16-1 are open and vice versa. Switch contacts R17-1 are closed at homeposition.

The embodiment 0f FIGS. 6, 7, 8 and 10 Broadly speaking, the mode ofoperation of the embodiment represented by FIGS. 6, 7, 8 and l0 is tocause the drum motor 20 to step in response to a pulse drawn from thepulse source 120, to stop the stepping operation in response to the deadcentering means 108, and to reset the stepping control circuit for thenext operation in response to termination of the pulse. In the disclosedembodiment, the pulse is generated yby aligning one of the slots in thelight chopping `disc 135 with a photocell and a light, thereby toactuate said switches. More specifically, the pulse causes switch RL-l(Figs. 7 and 10) to close thereby to start the motor 20 and move it olfdead center. Termination of the pulse restores switch RL1 as well as therest of the stepping control circuit 126 to appropriate positions,thereby resetting the means 126.

The starting procedure for this embodiment is arranged to bring the drummotor and drum into a timed relationship with the rotating lightchopping disc 135. Also, the entire starting procedure arranges thecircuit so that switch RL1 may operate as just described.

During starting there are two phases: skipping wherein only the drummotor 20 runs, and the drum is rotated until the rst programming pin P1engages its corresponding switch L1 and thereby starts the timing motor136, and then a dwell of the drum during which time the timing motordrives the disc until a first pulse is produced to thereby start thecontrol functions via L5, L6 The drum subsequently is stepped responsiveto subsequent pulses. These two phases may also be described as: movingoff home to zero position, and dwelling until zero time is establishedby the first pulse thereby 'beginning the control of functions. Thelatter position is termed the Zero time position because that is when`the drum motor 20 and the pulse source (i.e. disc motor 136) arebrought into the proper timed relationship for carrying out theremaining stepping operation.

A description of the operations of the embodiment of FIGS. 8 and 10 willfacilitate an understanding of the construction. At the outset, thevarious manually operated switches are moved to the positions shown inFIGS. 8 and 10 and switch 158 is closed to provide power. Switch 185selects row P1 and switch L1 as the program, and switches 139, 140select the light and light `cell corresponding thereto. Moroever, asybest illustrated in FIG. 1, for this embodiment, the row of pins P1 isarranged with all of the pins positioned adjacent each other andconsecutively so that stepping operationsv during the control cycle arefrom one adjacent pin to the next whereby the program switch L1 ismaintained closed. Moreover, attention is directed to the gangedswitches R16-land R17-1 (FIG. 10) which are adjusted so that the latteris closed at the home position while the former is open at suchposition. Two relay coils R16 and R17 are alternately operated torespectively position the switches so that one is open when the Ztl?other is closed. As it turns out, R16-1 remains closed during normaloperations and R17-1 is open, the respective positions being reversed atthe home position.

There are two home positions involved-one for the drum 2 and one for thelight chopping disc 35. The disc is driven to its home position by thehigh speed motor 222 which conveniently is mounted on the same shaft asthe synchronous timing motor 136.

Referring first to FIG. l0, the starting circuit 220 has a master switch230 which starts ,the operation of this embodiment by being manuallyclosed to thereby actuate the convenience relay R11 and to close the twocontacts controlled thereby in order to set up the conditions foractuating the starting switch holding coil R12. Coil R12 is in serieswith the homing switch H1 across the power supply and is thereforedisabled at the instant of starting because H1 is open at home.

However, referring to FIG. 7, the motor 20 is moved away from its homeposition by reason of a circuit through normally closed contacts R14-3.When the motor is oli home, the holding coil R12 is enabled and changesthe position of the contact switches controlled thereby, thus holdingitself in and maintaining a power supply to the entire system until suchtime as the cycle has been completed. In order to do this, the homingswitch H1 closes.

Also, when the motor moves olf dead center, switch 103 closes andenergizes relay R20 which in turn energizes relay R21. The contacts ofrelays R20, R21 have now changed state from that shown in FIG. 7.

With power now being supplied to the motor and to the system, the motor20 starts and drives through a skipping operation (i.e. moving over deadcenter) until the rst pin P1 (or P2, P3, P4 according to setting ofselector switch 185') closes its corresponding switch L1 (122 in FIG.6). The drum motor 20 now goes through an initial dead centeringoperation after which the drum dwells until it is time to step to thenext succeeding pin after the disc has furnished the first pulse.Referring for a moment to FIG. 7, the initial dead centering operationis carried out by a circuit to the motor through the normally closedcontacts of R19-3 and of R14-3, the cross coupling lead 235, and acircuit including the dead centering switch 108 and the now-closed(normally open) contacts R20-3. Also, relay R21 is actuated by closureof switch R20-2. The purpose in actuating relay R21 is to open thecircuit through lead 236 to the coil R20.

With the switches in the circuit of FIGS. 7 and l() in the position justdescribed, the motor 20 dead centers in response to opening of theswitch 103 because all other channels for power delivery have beendisabled by opening appropriate switches. The channel through switchR14-3 is opened in response to closure of L1 when the three positioningrelays R14, R15 and R16 are actuated to change the position of theirrespective contacts as shown in FIGS. 7 and l0. Pulse source motorselector R14 is thus actuated to select motor 136 for the duration ofthe cycle, at the same time rejecting the homing motor 222 and thehoming light by opening the switch R14-1. The drum motor control circuitswitch R14-3 is also opened at this time so that the dead centeringoperation can take place in response only and solely to the deadcentering switch. The pulse source enabling switch control coil R16 isactuated in response to the closure of L1 and simultaneously with themotor selecting relay, thereby turning on the motors by closing switchR16-1 and opening the ganged contact R17-1. The pulse source is now inoperation, the motor 136 driving the disc and power being delivered tothe amplifier 225 through the transformer 224.

Simultaneously with operation of relays R14 and R16, the function andhoming setup relay R15 is actuated to disable the homing setup relay R17for the remainder of the control program (i.e. until switch L1 is open).The

21 function setup relay also sets up the circuit to the function relayR1 of FIG. 8 by closing switch R152 to thereby set up a circuit to thezero time setup relay R18, the latter remaining de-energized until therst light pulse cornpletes a circuit by closure of light relay RL-S.

Responsive to the closure of R18-1, a circuit through lead 238 iscompleted to relay R1 (FIG. 8) thereby causing the function switchesR1-1, R1-2 to close. Any pins axially aligned with P1 on the drum maynow close their respective switches L5, L6 to actuate the functioncontrol means designated generically for convenience as solenoids 159,160.

In review, during startup the drum drives to the first pin in theselected row at which point the pulse source is started in operation byturning on the motor 136 and by actuating the function relay R1. Thedrum dwells in this position until the rst pulse, causing certainswitching operations, is sent into the system responsive to aligning alight 130, a cell 132 and a slot in the disc, as is shown in FIG. 6.During the dead centering operation or start up, the two reset relaysR20 and R21 are actuated thereby changing the position of all of theircontacts and in particular closing contact R20-3 and R20-4. Relays R20,21 are reset responsive to the first light pulse. The relay R20memorizes the fact that the drum motor is off dead center while therelay R21 responds to the disappearance of a pulse to disable R20 andthereby reset the circuit of FIG. 7 for a next succeeding pulse, in afashion to now be described.

Up to this time there has been no pulse sent into the system. The firstpulse is utilized to arrive at the zero time by starting the controlfunction and by resetting the circuit 126 for the next succeeding pulse.Means 124b, particularly relay coil R19, memorizes the first (zero time)light pulse. There has been no control function carried out because nocircuit to the function relay R1 via lead 238 has been completedthisrequiring closure of either switch RLS or switch R18-1. The pulses areof long enough time duration that the motor 20 has an opportunity todrive to its next succeeding dead center position, that is, to move thedrum one stepping increment, at which time or later the pulse ends andthereby resets the circuit means 126 as will shortly be described.

With the appearance of the first pulse, the light relay RL changes thesense of its three contacts to close both RL-l (in circuit 12d-see FIG.7) and RL-3 and at the same time to open contact RL-2. Closure of RL-Sactuates relay R18 `and causes it to close both Iof its switches R18-1(thereby holding itself in position) and R18-2 (thereby setting up relayR19). Relay R19 does not actuate this time because both of the switchescapable of energizing it (R19-1 and RL2) are open: actuation and pulsememorization occurs when the rst pulse ends and R12 closes. However,relay R19 does serve to memorize, for the duration :of the programcorresponding to row P1, the fact that there has been a complete firstpulse and since this pulse is the zero time of the system, it does allowenergization of relay R1 responseive to the closure of switch RL-3 whichis connected by lead 238 to R1. When the first pulse of light disappearsthe light relay RL switches all return to the positions shown in FIG.and in response to this, there now being a circuit through RL-2, relayR19 is energized.

Function relay R1 of FIG. 8 is energized via RL-3 and RL15-2 (nowclosed) in response to the appearance of the rst pulse. This starts thecontrol functions for those having pins P5, P6 axially aligned with P1on the drum. Relay R1 remains energized due to contacts R181 creating aselfeholding circuit for coil R18 and also to lead 238.

Responsive to the energization of relay R19, all of its contacts changesense so that R19-3 (FIGS. 10 and 7) is opened and switches R19-1 andR19-2 are closed. Closure of R19-1 maintains relay R19 in an energizedposition so that it has the effect of memorizing the first pulse oflight, i.e. of memorizing arrival at zero time for starting the controlcycle. In review, the first pulse of light energizes relay R1 andpermits the function switches to energize selected functions while atthe same time closing the switch R19-2 and opening R19-3. Operation ofthe latter two, as best seen in FIG. 7, serves to set (and reset) thesystem of FIG. 7 for sequential steps of operation. A channel to startthe drum motor 20 has now been created which is responsive only to thepulses appearing to cause closure of the light relay switch RL1. Thischannel as best seen in FIG. 7 extends from the starting switch throughthe now-closed contact R19-2, the now open contact RL-l, the lead 235,the now closed contacts R20-4, thence to the motor 20.

The contacts R20-4 have been returned to their closed position bydeenergization of relays R20 and R21 when the pulse terminates therebyopening the switch RL1 which shuts oit power to relays R20 and R21.

With the system now at zero time and the rst pulse having been memorizedby relay R19, the entire system remains in position until the next pulseis created. The drum remains stationary during this time but the motor136 continues to drive the disc thereby to present the next succeedingslot and generate the required pulse. When this pulse appears, theswitch RL-1 is closed and completes a circuit from the starting switchto the motor via a bypass around the dead centering switch 108. Thebypass is through the lead 235 and normally closed contacts R20-4. Whenthe motor moves off dead center position, the dead centering switch 108is closed and thereby causes the relays R20 and R21 to energize insequence. This breaks the circuit through switch R20-4 butsimultaneously establishes a circuit through switch R20-3. The motorcontinues to drive until it arrives at dead center whereupon switch 108comes open and the motor stops. As previously explained, the pins on thedrum are arranged in a solid row (see FIG. 6) so that the switch L1remains closed. However, new functions are initiated as far as thecontrol system is concerned by the particular arrangement of pins in theother rows to energize function switches such as L5, L6 The pulse has atime duration sufficient to allow the motor to step to dead center asjust described. This is achieved by providing the slots 137 withsuicient peripheral length so that the pulse is sustained despite thefact that the motor 136 continues to run throughout the cycle. Afterdead centering, the light slot 137 moves out of the beam, cuts off thelight, and thereby the pulse terminates.

When the pulse terminates, the motor control System of FIG. 7 resetsitself. Resetting is necessary because the dead centering switch hasenergized relays 20 and 21 which remained in that condition as long asthe switch RL1 was closed. Thus, termination of the pulse changes thelight relay RL and causes the switch RL1 to come open thus deenergizingthe relay 20 and 21 and thereby resetting the system of FIG. 7.

During a control cycle, the above running procedure continues byproviding pulses to start the motor by closing switch RL-l, stopping thedrum motor responsive to the dead centering switch 108, and thenresetting the system of FIG. 7 by opening switch RL1 responsive to thetermination of the pulse. This allows the drum motor to start inresponse to the beginning of a pulse, to stop responsive to driving toits next step, and then for the system to reset itself responsive totermination of the pulse. In accomplishing this, a bypass around thedead centering switch is provided so that the motor can jog off deadcenter.

After completing the cycle of operations, both the drum 20 and the lightchopping disc must be brought to their appropriate and respective homepositions. To accomplish this it is desired to turn on the high speedhoming motor 222 and to cause the drum motor to drive so that it movespast any successive number of dead center positions until both the drumand the disc

5. A STEPPING SWITCH FOR STEPPING THROUGH A CYCLE OF ELECTRICAL EVENTSIN STEPS EACH OF A DISCRETE TIME INTERVAL AND FOR SELECTING FOR EACHSTEP ONE DISCRETE INTERVAL FROM A PLURALITY OF SUCH INTERVALS, ANDCOMPRISING IN COMBINATION A PLURALITY OF TIMING MEANS, EACH FOROPERATING FOR A DIFFERENT PREDETERMINED DISCRETE TIME INTERVAL AND FORRESETTING ITSELF FOR ITS OWN DISCRETE TIME INTERVAL AT THE END OF EACHDISCRETE TIME INTERVAL OF OPERATION THEREOF; A REVOLVABLE ELECTRICMOTOR; A STARTING SWITCH FOR SAID MOTOR; CIRCUIT MEANS FOR CONNECTINGSAID STARTING SWITCH TO SAID MOTOR; MOTOR CONTROL SWITCHING MEANSCONNECTED IN SAID CIRCUIT MEANS FOR PROVIDING A PLURALITY OF ELECTRICALPATHS THERETHROUGH, EACH OF SAID PATHS BEING SELECTIVELY OPENED ANDCLOSED IN ACCORDANCE WITH A PREDETERMINED PROGRAM ENCODED ON THEHERINAFTER DEFINED MEMORY DEVICE; A TIMER SELECTION MEANS FOR SELECTINGONE OF SAID PLURALITY OF TIMING MEANS AND FOR DISABLING THE REMAINDER OFSAID PLURALITY IN ACCORDANCE WITH A PREDETERMINED PROGRAM ON THENEXT-SAID MEMORY DEVICE; A MEMORY DEVICE DRIVEN BY SAID MOTOR AND HAVINGA PART THEREOF A MEANS FOR DEFINING SAID PREDETERMINED PROGRAM INCLUDINGA PROGRAMMING MEANS FOR ENABLING ALL OF SAID TIMING MEANS RESPONSIVE TOMOVEMENT OF SAID MEMORY DEVICE TO A PREDETERMINED POSITION BY SAIDMOTOR, SAID MEMORY DEVICE MEANS FOR DEFINING ALSO INCLUDING MEANS FORENGAGING AND OPERATING SAID TIMER SELECTION MEANS IN ACCORDANCE WITHSAID PROGRAM RESPONSIVE TO SAID MEMORY DEVICE BEING DRIVEN BY SAID MOTORTO SUCH PREDETERMINED POSITION; SAID MOTOR CONTROL MEANS HAVING A MEANSFOR DISABLING ONE OF SAID PLURALITY OF PATHS IN RESPONSE TO SAIDPROGRAMMING MEDANS ARRIVING AT SAID PREDETERMINED POSITION; SAID MOTORCONTROL MEANS FURTHER INCLUDING A MEANS FOR KEEPING SELECTED ONE OF SAIDPATHS, EACH SELECTED PATH CORRESPONDING RESPECTIVELY TO ONE OF SAIDTIMERS, DISABLED DURING THE DISCRETE TIME INTERVAL OF OPERATION OF ITSRESPECTIVE TIMER AND TO ENABLE COMPLETION OF A CIRCUIT THROUGH SAID PATHIN RESPONSE TO THE RESPECTIVE TIMER HAVING RUN FOR ITS TIME INTERVAL,THEREBY TO START SAID MOTOR; A FIRST DEAD CENTERING MEANS FOR KEEPINGSAID TIMING MEANS DISABLED UNTIL SAID MOTOR REACHES A PREDETERMINEDPOSITION AND FOR STARTING THE TIMING MEANS SELECTED BY SAID SELECTIONMEANS RESPONSIVE TO SAID MOTOR ARRIVING AT A PREDETERMINED MOTORPOSITION; AND SECOND DEAD CENTERING MEANS FOR MAINTAINING A PATH THROUGHSAID SWITCHING MEANS BETWEEN SAID MOTOR AND SAID STARTING SWITCHWHENEVER SAID MOTOR IS NOT IN SAID PREDETERMINED MOTOR POSITION, AND FOROPENIN SUCH PATH WHEN SAID MOTOR IS IN POSITION, SAID MOTOR CONTROLMEANS INCLUDING SAID SECTION DEAD CENTER MEANS, ALL THE ABOVE-RECITEDPLURALITY OF PATHS TO SAID MOTOR BEING DISABLED DURING THE DISCRETE TIMEINTERVAL THAT THE SELECTED ONE OF SAID TIMING MEANS IN RUNNING, TIMINGMEANS SELECTED TO RUN NOT STARTING UNTIL THE MOTOR ARRIVES AT DEADCENTER.